yep. I have exactly the same situation as you. EFH with server in the basement and the same problems with the Nest system. I sent the parts back and bought a mesh system from deco (TP-link). It works great together with the sunrise modem, without complicated workarounds and easy installation and Management. Any time again!
I bought the set of 3 for WLAN distribution in an apartment block. The "server" is located in the basement and includes a switch for Internet distribution throughout the house. Internet comes via the Sunrise router, which is connected to the server. When the first Wifi point (Accsess) was installed, it still looked like it would be a simple matter (very good connection, according to the speed test). During the subsequent installation of the second Wifi Point, there were already problems with a weak connection etc., even though this point was connected to the Internet cable from the switch. With the third Wifi Point, no connection was possible at all. Despite various attempts, the product could not be put into operation, which almost made me despair. I've now given up and am considering returning the product, which would be a shame, as the aim is still to have WiFi coverage throughout the house.
Does anyone have any ideas about what else could be done here?
I had exactly the same problem. In my case, it was double NAT and a Wi-Fi preconfiguration that prevented the Nest points from connecting to wired, even with the RJ45 cable plugged in. Here are the essential points to check 👇
1. Set the Sunrise modem to modem mode (via the Sunrise interface). In the Sunrise interface, activate Enable Modem Mode. Deactivate Router Mode. The Nest Pro must be the only router on the network.
2. For each Nest point Connect the RJ45 cable before powering the Nest. Wait for it to start up: it will then detect the wired network (wired backhaul). In the Google Home app → Wi-Fi → Devices, check that the Connection type line = Wired or it will display the IP address (not Wireless).
3. If a point remains "Wireless Delete it in Google Home. Reinitialise it (factory reset). Reinstall it with the Ethernet cable already connected.
4. Avoid the pitfalls Use only one router (no double NAT). The switch must be unmanaged, with no VLANs or exotic PoE. Restart the entire network after making any changes.
In my case, the main unit is connected directly to the provider modem and the others are connected via Wifi. As this is a mesh system, the units must be able to communicate with each other. This is usually done via a separate Wifi band (backhaul). Unfortunately, Google does not describe this in more detail. However, I think that a switch interrupts this communication. If the connection between two units is weak, you can also connect them directly via an Ethernet cable. The entire setup is only possible via the Google Home app. It works perfectly for me, only the range of the individual units could be better.